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Hydrodesulfurization Catalysis Fundamentals
Published in Deniz Uner, Advances in Refining Catalysis, 2017
Organosulfur compounds show different HDS reactivity depending on their structure. Desulfurization of aliphatic organosulfur compounds (e.g., alkyl and aryl thiols [RSH], thioethers [RSR’], and disulfides [RSSR’]) is easier than the aromatic thiophenes [14]. The reactivities of aromatic organosulfur compounds differ in the following order: thiophene > alkylated thiophene > BTs > alkylated BT > DBTs and alkylated DBT without substituents at the 4 and 6 positions > alkylated DBT with one substituent at either the 4 or 6 position > alkylated DBT with alkyl substituents at the 4 and 6 positions [15,20,21]. The general trend is that low-molecular-weight compounds are more readily desulfurized than high-molecular-weight compounds. Furthermore, for DBTs, methyl substitution at the 4 or/and 6 positions results in reactivity decrease. This is attributed to a strong steric effect, arising from the methyl substitution at the 4 or/and 6 positions [17].
Chemicals from Non-hydrocarbons
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Organosulfur compounds are used in pharmaceutical products, dyestuffs, and agrochemicals. Many drugs contain sulfur, early examples being antibacterial sulfonamide drugs (sulfa drugs) and most β-lactam antibiotics, including the various penicillin derivatives, cephalosporins, and monobactams contain sulfur. Mercaptan derivatives (also called thiols—the function group is the—SH group—and informally represented as R–SH) are a family of organosulfur compounds. Some are added to natural gas supplies because of their distinctive smell, so that gas leaks can be detected easily. Others are used in silver polish, and in the production of pesticides and herbicides.
Aryl sulfonyl chlorides and sodium aryl sulfinates: non-volatile, non-stench, and non-toxic aryl thiol surrogates for direct aryl-sulfenylation of C–H bonds
Published in Journal of Sulfur Chemistry, 2020
Xiaohui Lu, Qicheng Yi, Xicai Pan, Peifang Wang, Esmail Vessally
Organosulfur compounds are an important subclass of organic compounds that contain at least one C–S bond in their structure [1]. These compounds play a crucial role in the field of medicinal and agricultural chemistry [2,3]. In this family of organic molecules, thioethers (organic sulfides; R-S-R’) has attracted a lot of attention in drug discovery programs due to their broad spectrum of biological activities including anticancer, antibacterial, antiretroviral, antiarrhythmic, antipsychotic, anti-allergy, antiplatelet, anti-inflammatory, and antimuscarinic activities [2,4]. Interestingly, more than thirty currently marketed pharmaceuticals contain at least one thioether motif (Scheme 1(a)) [4]. Furthermore, this privileged moiety is diversity found in various agricultural pesticides. Selected examples of some thioether containing pesticides are shown in Scheme 1(b). Those are chlorbenside (useful in controlling of mites and ticks) [5], ethiofencarb (useful in controlling of aphids) [6], and aldicarb (useful in controlling of various insects) [7]. Taking into consideration widespread biological activities of thioethers, it has been of great synthetic interest to develop efficient and general methods for the fabrication of the titled compounds from simple, non-toxic and easily accessible starting materials.
Methods for the direct synthesis of thioesters from aldehydes: a focus review
Published in Journal of Sulfur Chemistry, 2020
Noor H. Jabarullah, Kittisak Jermsittiparsert, Pavel A. Melnikov, Andino Maseleno, Akram Hosseinian, Esmail Vessally
Organosulfur compounds are defined as organic compounds containing at least one carbon–sulfur bond. These compounds are present in a significant number of natural products, pharmaceutical agents, and agrochemicals [1–3]. Thioesters with the functional group of R–S–CO–R′ are one of the most important members of this family of organic molecules which are widespread in biochemistry as key intermediates in many reactions, including the formation of fatty acids, esters, polyketides, and nonribosomal peptides [4]. They are also versatile building blocks for the synthesis of various natural products [5–7] and biodegradable polymers [8]. In the light of wide importance of thioester derivatives in various research fields, the development of new and efficient synthetic routes for their construction has been subject to intense study in recent years.
Direct C–H bond sulfenylation of (Het)arenes using sulfonyl hydrazides as thiol surrogate: a review
Published in Journal of Sulfur Chemistry, 2019
Akram Hosseinian, Sattar Arshadi, Shahriar Sarhandi, Aazam Monfared, Esmail Vessally
The direct formation of carbon–sulfur bonds represents a key step in the synthesis of many organosulfur compounds which are prevalent in natural products, pharmaceuticals, agrochemicals and organic materials. Over the past decades, various sulfenylating agents such as thiols, disulfides, sulfenyl halides, N-thioimides, and sulfinate salts have been developed in this chemistry; however, high cost, toxicity, volatility, and instability of many of these sulfenylating agents limit their practical applications. Thus, the development of new sulfenylating agents for these reactions is highly desirable. Sulfonyl hydrazides as inexpensive, readily accessible, high stable, odorless, non-toxic, and environmentally friendly thiolating agents have drawn considerable attention in recent years. As illustrated, these compounds have been successfully utilized in the synthesis of various synthetically and biologically important (hetero)aryl thioethers through direct and selective C–H bond sulfenylation of corresponding (hetero)aromatic compounds wherein H2O and N2 are the environmentally benign by-products of this transformation. Interestingly, most of the reactions covered in this review could be scaled up to provide multigram quantities of desired products. However, in some cases, the reactions were limited to the use of aromatic sulfonyl hydrazides since low yields were obtained with aliphatic and sulfonyl hydrazides. We conclude this review by hoping that it will stimulate researchers and serve as inspiration in their future work.